1. Field of the Invention
The present invention relates to a sealing device sealing a shaft periphery of a section which tends to be exposed to muddy water or the like from the outside, such as a wheel bearing of a vehicle or the like, and more particularly to a sealing device which is provided with such a structure as to prevent the muddy water or the like from making an intrusion into a slide section of an oil resisting seal lip.
2. Description of the Conventional Art
Since a sealing device used in a wheel bearing device of a vehicle, a transfer device or the like is easily splashed with muddy water or the like from the outside, it is necessary to inhibit the muddy water or the like from making an intrusion into a slide section of an oil resisting seal lip to the utmost so as to prevent a reduction of a sealing performance in the oil resisting seal lip as much as possible. FIG. 13 is a half sectional view of an installed state and shows one example of this kind of sealing device in accordance with a conventional art by cutting along a plane passing through an axis O.
In particular, in FIG. 13, reference numeral 201 denotes a housing of a transfer device of a vehicle, reference numeral 202 denotes a rotating shaft which is inserted to the housing 201 transversally (in an approximately horizontal direction), and is supported via a bearing 203 in a rotatable state around an axis O, reference numeral 204 denotes a sleeve which is fixed by a nut 205 as well as being spline-fitted to an outer periphery of the rotating shaft 202, and reference numeral 100 denotes a sealing device which is positioned at an outer side in an axial direction of the bearing 203 and is attached to an inner periphery of the housing 201.
In more detail, the sealing device 100 is constructed by an oil seal provided with an oil resisting seal lip 101 which extends to the bearing 203 side, and an external seal lip 102 and a dust lip 103 which extend to an opposite side (an outer side) to the oil resisting seal lip 101. The oil resisting seal lip 101 is structured such as to prevent leakage of lubricating oil within the bearing 203, by being slidably brought into close contact with an outer peripheral surface of the sleeve 204, and the external seal lip 102 is structured such as to be slidably brought into close contact with a seal flange section 204a formed in the sleeve 204 and the dust lip 103 is structured such as to be slidably brought into close contact with an outer peripheral surface of the sleeve 204, thereby preventing the muddy water or the like from making an intrusion into the oil resisting seal lip 101 side. Further, a labyrinth seal is formed in an outer side of the external seal lip 102 by making a dust cover 104a extended from a reinforcing ring 104 of the sealing device 100 come close to an outer diameter end section of the seal flange section 204a, thereby devising to inhibit the muddy water or the like from making an intrusion (refer, for example, to Japanese Unexamined Patent Publication No. 9-144891).